1. Field of the Invention
The present invention relates to an apparatus for, and method of, automated production, and/or packaging and/or testing of fiber optic devices including optical fiber system components and optical fibers, and more particularly, to an apparatus for, and method of, automatically manufacturing/forming, packaging and testing fiber optic devices in a rapid, accurate, repeatable, and reliable manner.
2. Background of the Related Art
Currently, a limited amount of effort and/or development and/or progress has been made in the area of automating the production process of fiber optic devices. For example, in Robert Frank Swain, "Automated Fabrication of Fused Fibre Optic Couplers," a dissertation published by the Heriot-Watt University, Edinburgh, Ireland (1993), submitted herewith and incorporated by reference herein (hereinafter "dissertation"), one example of an automated production facility is proposed, illustrated in FIG. 1. The production facility is designed for the manufacture of fused biconical tapered (FBT) devices that are manufactured by removing the plastic buffer coating then twisting a number of fibers together. The fibers are then heated using an oxy-hydrogen flame or furnace, which when soft, fuse together and are drawn axially using stepper motor stages.
The apparatus in FIG. 1 has a twin reel fibre tensioning and metering unit 4 with the facility to mount either lasers or detectors directly to the reel. Electrical signals are taken back to the control system via slip rings mounted on the back of the fiber reels. This unit 4 allows fibers 2 to be drawn directly from the reel to the working zone of the apparatus. Unit 4, as admitted by the dissertation, is a preliminary design that has yet to be integrated fully in the apparatus.
The automatic fiber twisting mechanism 6 works by lapping the fibers over one another using a rotary chuck. Axial twisting is limited by the micro-ball bearing assemblies through which the fibers pass. The twisting mechanism is operated by a stepper motor driver under computer control within the operating sequence. The twisted fibers have to be clamped side by side and held in intimate contact so that when heated to a sufficiently high temperature, the fibers will fuse together.
An automated fiber buffer stripper 8 uses a combination of heat and vacuum to evaporate the plastic buffer material from the fiber. This technique is used as a method for recycling acrylic polymers in the plastics industry. The fiber clamp 10 consists of a soft silicone rubber pad that traps the fiber between itself and the flat metal backplate. The force applied to the fiber is normal to the metal back plate. The fusion and drawing module includes the means by which the fibers are heated. The furnace 14 must be positioned correctly about the fibers to be fused together.
The furnace is essentially a resistance heater with 11 individual elements operating in an argon atmosphere, under computer control. Computer control of the furnace takes the form of an 11 element proportional, integral, differential (PID) controller which continually adjusts individual element supply power to suit the furnace loading and set point temperature.
When the fibers are softened, they begin to fuse, and at this point an axial force must be applied to the fibers to elongate them. This drawing operation is achieved by a stepper motor stage that incorporates the fiber clamping system. Due to the way in which the rig is designed, only one side of the coupler is drawn via moving fiber clamp 12. The stepper motor draw table is mounted onto an air bearing which is in turn restrained by a proving ring. With the air bearing floating, the axial tension in the fibers is registered. The output from the strain gauge is fed back to the computer controller so that temperature and draw rate may be set.
Once the fibers have been drawn into a coupler, the coupler must be "packaged" to provide strength so that the coupler may be handled without breakage. A substrate positioner has a cassette of substrates which can be selected and manoeuvred into position under the coupler prior to manual application of the adhesive used to hold the coupler to the substrate.
Other proposed production facilities include the following publications: U.S. Pat. No. 5,386,490; U.S. Pat. No. 5,329,600; U.S. Pat. No. 5,013,117; Stevenson, et al., "Fibre-Optic Coupler Fabrication at AOFR," International Journal of Optoelectronics, Vol. 6, Nos. 1/2, p.127 (1991); Yokohama, et al., "Fiber-Coupler Fabrication with Automatic Fusion-Elongation Processes for Low Excess Loss and High Coupling-Ratio Accuracy," Journal of Lightwave Technology, Vol. LT.-5, No. 7, p.910 (July 1987); Moore, et al., "Mass Production of Fused Couplers and Coupler Based Devices," SPIE Vol. 574, Fibre Optic Couplers, Connectors and Splice Technology II, p.135 (1985), all of which are hereby incorporated by reference.
However, I have realized that the above processes suffer from various drawbacks and/or disadvantages. For example, the above processes do not generally provide sufficient tools and/or automation to accurately and/or reliably transport or convey a fiber optic device through the production process. In addition, the above processes utilize equipment that is itself complex, and/or makes the production process complex, such that the production process is overly complex, expensive and/or impractical for rapid production of high quality fiber optic devices.
Further, the above processes also rely generally on production and/or manufacturing techniques that do not provide good yield results. For example, the use of epoxy makes the manufacturing process difficult. Similarly, the use of a crimping action can damage a fiber optic device, such as a ferrule and/or optical fiber. Accordingly, an optical fiber and/or fiber optic device produced and/or secured according to these prior techniques often times is not useable.
I have also realized that the above processes are difficult to automate because of the inability of the above processes to adequately design production steps geared and/or designed for an automated process. I have determined that process steps that can be advantageously broken down or separated into the steps of pre-production positioning, production, production monitoring, post-production positioning, testing, packaging, and post-packaging positioning.
I have therefore determined that it is desirable to provide accurate and consistent production of fiber optic devices using a process that is automated.
It is also desirable to provide production techniques to completely automate the manufacture of fiber optic devices.
It is also desirable to provide a production process capable of automatically manufacturing large volumes of fiber optic devices in a rapid, reliable, and inexpensive manner.
It is also desirable to provide a production process capable of at least one or more, and/or a combination of, automated pre-production positioning, production, production monitoring, post-production positioning, testing, packaging, and post-packaging positioning.